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Migraine is a common disabling disease with a complex pathophysiology. Headache is a frequent side effect after intravenous adenosine administration, although adenosine receptor antagonist, caffeine, relieves migraine headache. These observations suggest a possible involvement of adenosine signaling in headache and migraine pathophysiology. In a randomized, double-blinded, placebo-controlled, crossover study, 18 participants diagnosed with migraine without aura received 120 µg/kg per minute adenosine or placebo over 20 minutes. Headache intensity, migraine-associated symptoms, vital signs, the diameter of the superficial temporal artery (STA), blood flow velocity in the middle cerebral artery (V MCA ), and facial skin blood flow were measured at baseline and every 10 minutes until 2 hours after infusion start. The primary end point was the difference in the incidence of migraine attacks after adenosine infusion compared with placebo. Eighteen participants completed the study. We found no difference in the incidence of migraine after adenosine infusion (7 of 18, 39%) compared with placebo (3 of 18, 17%) ( P = 0.29). Fourteen participants reported headache after adenosine infusion (14 of 18, 78%) compared with placebo (6 of 18, 33%) ( P < 0.01). Adenosine increased heart rate ( P < 0.001), facial skin blood flow ( P < 0.05), and STA diameter (AUC T0-20min , P = 0.01) and decreased V MCA (AUC T0-20min , P < 0.001) compared with placebo. Adenosine induced headache accompanied by a short-lasting (<30 minutes) dilation of intracerebral and extracerebral arteries. The nonsignificant migraine induction might be because of the presence of several adenosine receptors with counteracting signaling, highlighting the need of more selective modulators to dissect the implication of adenosine in migraine.

Objective To systematically review clinical studies investigating the involvement of adenosine and its receptors in migraine pathophysiology. Background Adenosine is a purinergic signaling molecule, clinically used in cardiac imaging during stress tests. Headache is a frequent adverse event after intravenous adenosine administration. Migraine headache relief is reported after intake of adenosine receptor antagonist, caffeine. These findings suggest a possible involvement of adenosine signaling in migraine pathophysiology and its potential as a drug target. Methods A search through PubMed and EMBASE was undertaken for clinical studies investigating the role of adenosine and its receptors in migraine, published until September 2021. Results A total of 2510 studies were screened by title and abstract. Of these, seven clinical studies were included. The main findings were that adenosine infusion induced headache, and plasma adenosine levels were elevated during ictal compared to interictal periods in migraine patients. Conclusion The present systematic review emphasizes a potentially important role of adenosine signaling in migraine pathogenesis. Further randomized and placebo-controlled clinical investigations applying adenosine receptors modulators in migraine patients are needed to further understand the adenosine involvement in migraine.

Background Adenosine is a purinergic signaling molecule with a wide range of physiological functions including anti- and pronociceptive properties. Adenosine receptors are expressed in the trigeminovascular system, and adenosine receptor antagonist, caffeine, relieves migraine headache. We performed a systematic review of the literature of preclinical data addressing the role of adenosine in migraine pathophysiology. Methods PubMed and EMBASE were searched for pre-clinical studies on the role of adenosine in migraine pathophysiology on September 5(th), 2021. Results A total of 2510 studies were screened by title and abstract. Of these, thirteen pre-clinical studies evaluating adenosine, adenosine A1, A2A and A3 receptors were included. These studies showed that adenosine signaling pathway is involved in controlling vascular tone. Furthermore, electrical stimulation of the trigeminal ganglion modulates the expression of adenosine A(1) and A(2A) receptors in the trigeminal ganglion and trigeminal nucleus caudalis implicating adenosine signaling pathway in pain transmission. Conclusion Preclinical studies showed that adenosine has a dual effect on vasodilation and trigeminal pain pathway due to different receptor activation, suggesting a possible role of adenosine in migraine pathophysiology. Studies investigating pharmacological characteristics of subtypes of adenosine receptors are needed to further elucidate their role as a potential target for migraine treatment.

Background: The paroxysmal nature of migraine is a hallmark of the disease. Some patients report increased attack frequency at certain seasons or towards the end of the week, while others experience diurnal variations of migraine attack onset. This systematic review investigates the chronobiology of migraine and its relation to the periodicity of attacks in existing literature to further understand the oscillating nature of migraine. Main body: PubMed and Embase were systematically searched and screened for eligible articles with outcome measures relating to a circadian, weekly or seasonal distribution of migraine attacks. We found that the majority of studies reported morning hours (6 am–12 pm) as the peak time of onset for migraine attacks. More studies reported Saturday as weekly peak day of attack. There was no clear seasonal variation of migraine due to methodological differences (primarily related to location), however four out of five studies conducted in Norway reported the same yearly peak time indicating a possible seasonal periodicity phenomenon of migraine. Conclusions: The findings of the current review suggest a possible role of chronobiologic rhythms to the periodicity of migraine attacks. Future studies are, however, still needed to provide more knowledge of the oscillating nature of migraine.